A network processor is a device that executes programs to handle packet traffic in a data network. A network processor is also often referred to as a network flow processor or simply a flow processor. Examples include network processor integrated circuits on router line cards and in other network equipment. In one example, a network processor integrated circuit is capable of receiving packets, classifying and performing atomic operations on the packets and associated packet data, and transmitting packets. Processors on the integrated circuit are called upon to perform processing functions that include using lookup tables stored in on-chip memories to find data structures that store information pertaining to different types of packets. A processor on the integrated circuit may also be called upon to determine and to log updated packet count and byte count information into appropriate tables in memory. As throughput requirements increase, ways of adding processing power are sought.
In one specific example, a network processor integrated circuit uses the flexible and expandable IXP2800 architecture. The IXP2800 architecture allows multiple high-speed processors (referred to as microengines) to access the same memory resources via a common command/push/pull bus. Due to use of the IXP2800 architecture and multiple microengines, increased processing power is brought to bear on the tasks of identifying data structures using lookup algorithms. If more throughput is required, then more microengines can be employed. If less throughput is required, then fewer microengines can be employed. The NFP-3XXX and NFP-6XXX families of network processor integrated circuits available from Systems, Inc. of Santa Clara, Calif. include a selection of IXP2800-based network processor integrated circuits having different numbers of microengines.